Reinforced footwear



Nov. 12, 1968 R. VOGEL REINFORCED FOOTWEAR 4 Sheets-Sheet 1 Filed March 18, 1966 Nov. 12, 1968 R. VOGEL 3,410,006

REINFORCED FOOTWEAR Filed March 18, 1966 4 Sheets-Sheet 2 Jm/en OFI Nov. 12, 1968 R. VOGEL. 3,410,006

REINFORCED FOOTWEAR Filed March 18, 1966 4 Sheets-Sheet 5 Nov. 12, 1968 I VOGEL 3,410,006

REINFORCED FOOTWEAR Filed March 18, 1966 4 Sheets-Sheet 4 g, i my Fig.10

i 34 L I Jm en/m" P 'm no Mye/ B MW MM United States Patent O 3,410,006 REINFORCED FOOTWEAR Raimund Vogel, Tuerkenstrasse 103, Munich, Germany Filed Mar. 18, 1966, Ser. No. 541,896 Claims priority, application Germany, Mar. 24, 1965, V 28,127; June 12, 1965, V 28,686 16 Claims. (Cl. 363) ABSTRACT OF THE DISCLOSURE A piece of footwear including a stiffening element made of plastic reinforced by two groups of reinforcing members inserted in the plastic. The reinforcing members may be yarns, wires, glass fibers, or the like. One group of reinforcing members is greater than the number of members in a perpendicular group, providing greater stiffness in a desired direction.

This invention relates to footwear, such as shoes and boots, and particularly to pieces of footwear provided with reinforcing elements.

More specifically, the invention is concerned with footwear distinguished by low weight, high rigidity, and the ability of maintaining its shape over an extended period of wear.

Additional objects of the invention include the provision of footwear which provides comfort and proper support to the foot of the wearer and others that will presently become apparent.

The several elements which constitute the load bearing structure of a shoe or boot do not have to be equally rigid in all directions. Rigidity is normally desirable in the sole only in a direction transverse to the longitudinal axis of the shoe or boot, and other structural elements of footwear should be similarly rigid in one direction and flexible in another direction perpendicular to the direction of maximum rigidity.

Each piece of footwear of the instant invention includes a reinforcing element which is generally plate-shaped so as to have two major surfaces. The reinforming element consists mainly of thermosetting plastic and is provided with inserts embedded in the plastic for imparting greater fiexural strength to the reinforcing element in one direction than in another, transverse direction. Both directions are approximately parallel to the major surfaces of the element. Reinforcing members elongated in a common direction essentially constitute the insert.

The elongated reinforcing members may be fibers in a fabric, roving, or strands of a bundle of parallel fibers. Glass and metals are the preferred materials for the reinforcing members, and the choice of thermosetting plastics for the reinforcing elements is very wide, embracing not only the various condensation products of formaldehyde with urea, phenol, or melamine, but also certain epoxy resins and crosslinked urethanes which are staple articles of commerce.

Other features, additional objects, and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which:

FIG. 1 shows a laminated reinforcing plate of the invention in cross section;

FIG. 2 shows a reinforcing insert for a ski boot according to the invention in a perspective view;

FIG. 3 illustrates the insert of FIG. 2 in position in a ski boot shown in phantom view, in side elevation;

FIG. 4 is a perspective view of a reinforcing insert for a mans shoe;

FIG. 5 shows a removable reinforcing insole of the invention in perspective view;

FIG. 6 illustrates the heel of a mans shoe in a fragmentary perspective View;

FIG. 7 shows a womans shoe equipped with a resiliently reinforced heel in side elevation;

FIG. 8 is a side-elevational sectional view of a shank reinforcement according to the invention;

FIG. 9 shows a reinforcing insert which cradles the rear portion of the foot in a shoe, the view being in frontelevational section; and

FIG. 10 shows a wedge sole of the invention equipped with a ventilating device in side elevational section.

Referring now to the drawing in detail, and initially to FIG. 1, there is shown a plate-shaped, laminated reinforcing element of the invention whose core 1 consists mainly of a cured thermosetting plastic, such as an epoxy resin composition, in which glass fibers 2 are inserted. The fibers are parallel to each other and to the major faces of the plate so that only one such fiber is visible in the drawing.

One face layer 3 consists of polyurethane foam and the other face layer 4 consists mainly of thermoplastic synthetic resin reinforced with an embedded fabric, not itself shown. The illustrated laminated reinforcing element is stiff in the direction of elongation of the glass fibers 2, but quite flexible transversely of that direction. When used in a boot for stiffening or reinforcing leather or other materials, the foam layer 3 is arranged as a lining to face inwardly toward the foot of the wearer, and the other, outer face, layer may be modified to assume such functions as are desired. It may consist of resin impregnated fabric only if it provides the outer surface of the shoe or boot.

The polyurethane foam of the lining layer 3 is capable of being permanently deformed under localized pressure after being attached to the core layer 1, and is shown, by way of example, to have a rounded shallow recess 5 in its exposed face for reducing pressure on a sensitive part of the foot.

The thickness of the core layer 1 may be varied as shown in FIG. 1 for corresponding variations in resilience of the plate member. Such variations, of course, can also be brought about by varying the spacing and thickness of the glass fibers 2. It is normally preferred to employ glass fibers as an insert in the thermosetting core layer, the fibers being preferentially elongated as a group in the direction of desired stiffness, and held together by a group of transverse fibers too few in number to affect the predominant unidirectional stiffness characteristics of the laminate. Such transverse fibers have been omitted from the showing of FIG. 1.

The core layer 1 is practically impervious to air, and the foam layer 3 is open-celled, to provide circulation of air and may be impregnated with thermosetting resins to some extend not to conflict with the desired porosity.

The use of the material shown in FIG. 1 is illustrated in FIGS. 2 and 3 which show a reinforcing insert for a ski boot and the ski boot with its reinforcement installed. The insert has a vamp portion 6 which is upwardly generally open, and a top portion 7 which is open in a forward direction. The two portions are connected by pivot pins 8 journaled in metal reinforcing strips 9 and 10 which are fixedly anchored in the two insert parts respectively. The common axis of the two pins 8, of which only one is seen in the drawing, approximately coincides with the pivot axis of the wearers ankle.

The front end of the vamp portion 6 includes a toe box and the rear end cradles the heel of the wearer. The

top portion 7 envelops his Achilles tendon. Upwardly open vertical slots 11 in the top edge of the vamp portion 6 facilitate flexing of the wearers foot in the metatarsal joints, and permit thermal expansion. The hinged connection of the two portions 6, 7 of the stiffening insert permits unrestricted flexing of the leg at the ankle in a forward and backward direction, while restraining lateral movement.

The ankle of the wearer is further stablized by a backstay reinforcement essentially consisting of an upright, resilient steel strip 12 fixedly anchored in the vamp portion 6 and upwardly extending into a guide channel 13 similarly fastened in the top portion 7 for connecting the top and vamp portion. Longitudinal movement of the strip 12 in the channel 13 is limited by an abutment pin 15 on the latter which is movably received in a slot 14 of the strip 12. This limits the relative pivoting movement of the insert portion 6, 7.

It will be appreciated that the reinforcing glass fibers, not themselves seen in FIGS. 2 and 3, mainly extend in an upward direction in the top portion 7 and in the parts of the vamp portion 6 other than the sole and the top of the toe box. The ratio of vertical to horizontal fibers is preferably about 20 to l. The reinforcing fibers in the sole and toe box are horizontal and transverse of the longitudinal axis of the boot. The upright front edges of the top portion 7 may be resiliently moved toward and away from each other as needed for entry into the boot or for lacing.

The insert shown in FIG. 2 is placed directly on the outsole 16, as is seen in FIG. 3, and the insole 18 is placed over the sole portion of the insert. The leather vamp and top 17 of the boot outwardly cover the insert, but it will be appreciated that the face layer 4 may itself provide at least a portion of the outer surface of the boot. The insole 18 is supported and protected by the reinforcing insert and may therefore be very light and flexible.

FIG. 4 shows a reinforcing insert for a mans shoe which may be employed for giving strength to a limp and pliable fabric upper, and for connecting the same to a sole, the upper and sole being adhesively fastened to the illustrated insert in a known manner, not shown. The insert consists of a plate member molded in the shape of a foot and perforated to form a skeleton of elongated strips 19 of the material shown in FIG. 1, with the glass fibers extending in the direction of elongation of most of the strips. The insert may be molded with its perforations as an integral unit in a manner known in itself.

The shoe reinforcing element shown in FIG. mainly consists of an insole having integrally attached thereto reinforcements for the rear portions of the vamp. The element is a plate of the type shown in FIG. 1 and slotted is such a manner as to leave spaced, narrow, transverse ribs 21 under the front part of the foot, and wider strips 20 mainly forming the rear part of the element, the ribs 21 and strips 20 being held together by slender longitudinal members 22. The reinforcing element is a unitary structure of thermosetting plastic reinforced by gl-ass fibers (not shown) which extend transverse of the axis of the shoe, that is, longitudinally in the ribs 21 and strips 20, but at right angles to the direction of elongation in the members 22.

The reinforcing element laterally stiflens the nonillustrated shoe, in the elongated cavity of which it is normally inserted on top of the outsole, without materially interfering with the flexing of the shoe during walking. The normally vertically extending end portions of the strips 20 provide full lateral support for the wearers heel particularly because they converge in an upward direction. When the apertures between the ribs 21, strips 20, and members 22 are closed by a thin layer of leather or other permeable fibrous material, there is obtained a insole providing orthopedic support for the foot of the wearer.

The glass-fiber reinforced plastic material of the in- 4 vention is eminently suitable for making heels. FIG. 6 shows only the load-bearing elements of the heel for a mans shoe which has a laterally and rearwardly open recess 23 between plate-shaped top and bottom elements 26, 24 consisting mainly of cured thermosetting epoxy resin reinforced with glass fibers which extend in the longitudinal direction of the shoe, and firmly connected at the front end of the heel only. The bottom element 24 is further reinforced by a narrow longitudinal leaf spring 25 of steel, and a similar spring may be provided for the top element 26. The recess 23 is normally filled with resilient foam material or the like which does not interfere with relative movement of the elements 24, 26, does not add significant weight to the heel, and has merely a decorative function.

The illustrated heel provides a particularly resilient walk and reduces fatigue.

The womans shoe shown in FIG. 7 has a heel consisting of thermosetting epoxy resin reinforced with glass fibers 29 which extend in an approximately vertical direction. The portion 27 of the heel adjacent the lift 28 has the shape of an elongated rod which is obliquely inclined relative to the surface on which the shoe is placed and is flexed under the weight of the wearer. A shoe provided with a high heel of the invention provides a soft and resilient walk not heretofore available in shoes of this type. The forward displacement of the lift 28 relative to the axis of the wearers leg induces a beneficial gait in which the foot performs a rolling movement on the balls of the toes.

FIG. 8 shows a shank reinforcement of the invention consisting of a body 30 of thermosetting epoxy resin provided with non-illustrated glass fibers embedded in the bottom part of the resin body and extending longitudinally in the same. The top of the shank reinforcement has parallel transverse slits 31 so that the shank reinforcement may flex resiliently in an upward direction from the illustrated position when relieved of weight during walking movement of the wearer, but sets a firm limit to downward movement of the superposed parts of the foot. The slits 31 extend over the entire width of the shank reinforcement and Over about two thirds of its thickness. The shank reinforcement shown may be integrally enlarged to form an insole under the heel of the wearer.

A laminated reinforcing element of the invention for the heel portion of a shoe is seen in FIG. 9. Its outer layer 32 consists of thermosetting plastic reinforced by non-illustrated glass fibers predominantly arranged in planes approximately parallel to that of the drawing, and of a lining layer 33 of foamed plastic. The upright portions of the insert converge in a direction away from the sole. The illustrated reinforcing element provides much firmer support than one having parallel or diverging upright portions.

The fiber-reinforced shoe material of the invention is substantially impervious to air. FIG. 10 shows the sole of a ski boot consisting of thermosetting plastic and longitudinal glass fibers (not shown), and provided with an automatic air pump.

A recess in the top face of the sole 34 accommodates a bulb 35 of rubber or other resilient material which slightly projects above the top face of the sole in the relaxed condition but can be depressed by a minimal force to be flush with the sole. A duct 36 of undulating configuration leads rearward and downward from the bulb 35 to an orifice 37 in an exposed surface of the sole 34, and. another duct 38 leads forward and upward to another orifice located under the sole of the wearer approximately mid-way between the toe and heel ends of the boot, not otherwis shown. Check valves 39, 40 permit flow of fluid through the ducts 36, 38 and the bulb 35 only in a direction inward from the orifice 37.

When pressure is applied on the bulb 35 by the foot of the wearer in the normal rhythm of walking, the bulb acts as a pump which draws air from the orifice 37 and discharges it under pressure from the duct 38. The downward inclination of the duct 36 toward the orifice 37 and the undulating configuration of th duct prevent water from being drawn into the boot.

Glass fibers are preferred for providing the desired anisotropic stiffness properties to the plastic reinforcing elements of the invention, but other elongated elements of glass or other materials may be employed to obtain at least some of the advantages of the invention. The use of wire or other elongated metal members of uniform cross section is specifically contemplated. It is most convenient to achieve preferential stiffness in one plane by employing a multiplicity of identical stiffening members most of which are elongated in a common direction, but similar effects may be achieved by using equal numbers of fibers elongated in two directions at right angles to each other, and by suitably selecting the modulus of elasticity of each group.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Where the outer surface of the shoe or boot consists of fabric, it is specifically contemplated to reinforce the fabric with wear resistant and/or cut resistant materials such as steel filings, wires, wire fabric and the like. These reinforcing members may be twisted with the yarn of the fabric, woven into the fabric, or adhesively or otherwise attached thereto.

What is claimed is:

l. A piece of footwear including a reinforcing element of thermosetting plastic and insert means embedded in said plastic for imparting greater flexural strength to said reinforcing element in one direction than in another direction perpendicular to said one direction, said insert means including two intersecting groups of reinforcing members respectively elongated in said directions, the number of reinforcing members elongated in said one direction being greater than the number thereof elongated in said other direction.

2. A piece of footwear as set forth in claim 1, wherein said element is laminated and generally plate-shaped and additionally includes a layer of synthetic foam material superimposed on one surface thereof, said surface facing inwardly of said piece of footwear, and said foam material being capable of being permanently deformed under localized pressure.

3. A piece of footwear as set forth in claim 1, having a top portion and a vamp portion, said reinforcing element being mounted in said top portion and shaped to extend about the Achilles tendon of a wearers foot conformingly inserted in said piece of footwear, the latter further comprising another generally plate-shaped reinforcing element of said plastic having insert means embedded therein for imparting greater flexural strength to said other reinforcing element in one direction than in another direction perpendicular to said last mentioned direction, the insert means of said other reinforcing element including a plurality of members elongated in a common direction, said other reinforcing element being mounted in said vamp portion, and pivot means connecting said reinforcing elements for pivoting movement abount an axis approximately coinciding with the pivot axis of the ankle of said inserted foot.

4. A piece of footwear as set forth in claim 3 wherein said first mentioned reinforcing element has two front edges extending downward in a common direction toward said vamp portion, the element being resiliently bendable for movement of said edges toward and away from each other, said other reinforcing element having two top edges extending rearward in a common direction toward said top portion, said top edges being transversely slotted.

5. A piece of footwear as set forth in claim 4, further comprising a connecting member fixedly mounted on one of said reinforcing elements and guide means on the other reinforcing element engaging said connecting member for guiding the same in a plane transverse to the axis of said pivot means, said connecting member being radially spaced from said axis.

6. A piece of footwear as set forth in claim 5, further comprising abutment means for limiting the relative movement of said connecting member and of said guide means, and for thereby limiting the pivoting movement of said reinforcing elements relative to each other.

7. A piece of footwear as set forth in claim 3, further comprising an insole and an outsole, said other reinforcing element having a sole portion interposed between said insole and said outsole.

8. A piece of footwear as set forth in claim 1, further comprising an upper and a sole, said reinforcing element being arcuately formed to define the shape of a foot and perforated, said upper and said sole being attached to said reinforcing element.

9. A piece of footwear as set forth in claim 1 comprising a sole, a heel and a lift on said heel, a portion of said heel adjacent said lift being substantially rod-shaped and at least partly constituted by said reinforcing element, said sole and said lift defining a plane of normal contact between said piece of footwear and the ground, said rod shaped portion being inclined in a direction obliquely inclined realtive to said plane, said closer spaced reinforcing members being elongated in said obliquely inclined direction.

10. A piece of footwear as set forth in claim 1, comprising a heel formed with a rearwardly and laterally open recess, said reinforcing element constituting a portion of said heel vertically bounding said recess in one direction, another reinforcing element similar to said first-mentioned element bounding said recess in the other vertical direction, and a steel member further reinforcing one of said elements.

11. A piece of footwear as set forth in claim 1, comprising an outsole and defining an elongated cavity therein above said outsole, said reinforcing element being superposed on said outsole in said cavity and being formed with a plurality of slots therein, said slots dividing said element into a plurality or ribs and a plurality of strips, said ribs and strips being elongated transversely of the direction of elongation of said cavity, said ribs being closely spaced in a forward portion of said cavity and said strips being arranged in a rearward portion of the cavity, the strips having each two end portions and another portion intermediate said end portions and adjacent said outsole, said end portions extending from said intermediate portion away from said outsole.

12. A piece of footwear as set forth in claim 1, having an elongated shank portion, said reinforcing element being embedded in said shank portion and said surfaces thereof constituting a top face and a bottom face, said top face being formed with a plurality of slits elongated transversely of the direction of elongation of said shank portion and spaced from each other in said direction.

13. A piece of footwear as set forth in claim 1, formed with an elongated cavity therein, said reinforcing element being located at the bottom of said cavity and being formed with a recess therein facing said cavity, a bulb member of resilient material located in said recess and projecting therefrom toward said cavity when in the relaxed condition, two duct means communicating with said bulb member and having respective orifices open to said cavity and to the outside of said piece of footwear, and check valve means in each of said duct means for permitting flow of fluid through said duct means and said bulb from one of said orifices to the other only.

14. A piece of footwear as set forth in claim 1, wherein said reinforcing element is generally plate-shaped and of arcuate cross section transversely of the longitudinal axis of said piece of footwear, said element having a sole portion and two portions normally extending upwardly from opposite sides of the sole portion and converging in a direction away from said sole portion.

15. A piece of footwear as set forth in claim 1, wherein at least one group of reinforcing members is constructed of fibrous glass.

16. A piece of footwear including a side reinforcing element of thermosetting plastic, and insert means embedded in said plastic for imparting greater flexural strength to said reinforcing element in a generally vertical direction than in a direction perpendicular to said generally vertical direction, said insert means including two intersecting groups of reinforcing members respectively elongated in said directions, the number of reinforcing members in said generally vertical direction being greater than the number thereof elongated in said other 2,367,481 1/1945 Burger 362.5 X

, FOREIGN PATENTS j 1,193,946 11/1959 Frances PATRICK D. LAWSON, Primary hammer. 

